This invention relates to an automatic transmission control system, and more particularly to a synchronous mesh-type automatic transmission control system for an automotive vehicle, wherein an actual throttle opening of an internal combustion engine is capable of being set equal to a target throttle opening in a short period of time during a speed shift operation.
A control device concerning a clutch and a throttle operation is disclosed in Japanese laid-open Patent No.60-35633 as an example of a prior art in this field. In the control device disclosed in this prior art, a clutch releasing speed and a throttle closing speed are controlled to prevent a shock or an engine blow-up while the clutch is being released at the outset of a speed shift operation. In more detailed description, the control device comprises a clutch actuator for controlling a release-connect operation of the clutch, a throttle control means for controlling an open-close operation of the throttle and a control unit. The control unit stores a clutch map ruling a clutch releasing speed in terms of an accelerator position detected, a throttle map ruling a throttle closing speed in terms of the accelerator position detected, and controls a throttle closing speed as well as a clutch releasing speed referring to the above maps by the clutch actuator and the throttle control means in a speed shift operation.
As above explained in an automatic transmission for an automotive vehicle in the prior art, the throttle opening is usually controlled based on the accelerator position as a parameter at the time of starting the speed shift operation. In this operation, a throttle moving speed is fixed once the speed shift operation has started. Therefore, when an accelerator is manipulated while the automatic transmission is functioning after it has started, it could take an extra time for setting the throttle opening if the accelerator is further stepped down, or a shock due to an instant speed transfer could occur if the accelerator is loosened, and both of these phenomena can be the cause of a wrongness feeling to a driver.
In view of the above, it is object of the present invention to provide a synchronous mesh-type automatic transmission control system for an automotive vehicle wherein a shock or a wrongness feeling for the driver is avoidable by keeping a setting time of a throttle opening approximately constant even when an accelerator is manipulated by the driver during a speed shift operation.
A synchronous mesh-type automatic transmission control system for an automotive vehicle comprises:
a transmission coupled with an internal combustion engine through an electro-magnetic clutch, and provided with the plural sets of gears having a different gear ratio with each other,
a shift-select actuator for coupling a set of gears selected from the plural sets of gears,
a throttle moved by a throttle actuator for controlling a rotating speed of the internal combustion engine by adjusting an intake air flow into the internal combustion engine,
a throttle actuator for controlling the throttle based on a stepped-down quantity of an acerator and a stored program for speed shift operation, and,
a control means supplies a signal to the shift-select actuator in order to control a speed shift operation by changing the plural sets of gears, and computes a target throttle opening and a throttle moving speed from a difference of an actual and the target throttle opening
wherein said control means controls the actual throttle opening depending on the throttle moving speed to transfer to the target throttle opening by controlling the throttle actuator after a gear change operation is completed.
Also in the synchronous mesh-type automatic transmission control system for the automotive vehicle, the control means determines the throttle moving speed periodically based on a control map stored in the control means.
Therefore, it is possible to provide the synchronous mesh-type automatic transmission control system as a required time for the throttle to move to the target throttle opening can be approximately constant regardless of the present actual throttle opening. Also the shock when the gear change operation is completed is capable of being prevented, and the wrongness feeling to the driver due to the prolonged time for setting the throttle opening is avoidable with the control system.
Furthermore, the larger is the difference of the actual and the target throttle opening, the larger the manipulating speed of the throttle becomes, and then the actual throttle moving speed is gradually slowed down as the throttle opening nears the aimed throttle opening. Accordingly, the throttle moving speed is capable of being controlled stably without an overshooting action.